In recent years, many household electrical appliances in houses such as televisions and mobile apparatuses such as mobile phones include communication functions such as wireless LAN (local area network) and Ethernet (registered trademark). By such devices each connecting to a network, cooperative operations between the devices can be attained.
For example, in a case where a mobile apparatus and household electrical appliances in a house are connected to each other, in order that only a proper user is allowed to be connected, a user has to set in advance authentication information such as an ID and a password to all the household electrical appliances in a house. This imposes burdensome operations on the user, which is a problem.
To solve this problem, for example, there is a first method in which a user presses a button provided in a household electrical appliance in a house, a mobile apparatus that has requested connection within a certain period of time is connected without authentication, and authentication information is automatically set, thereby reducing the work of setting authentication information by the user.
However, the first method has a problem in that the security is not ensured for a certain period of time.
Further, in order to solve such a problem, there is a second method in which, a short distance radio and a wireless technology having a high directionality are used to limit the physical distances and directions between the mobile apparatuses and the household electrical appliances in a house, and only a mobile apparatus that has requested connection from the limited area is allowed to be connected without authentication, thereby strengthening the security.
According to the second method, it is possible to configure a connection system in which connection is allowed in a specific area, such as in a room, but connection from the outdoors is not allowed.
Moreover, Patent Literature 1 discloses a technology, in which, for example, the distance between devices is measured at the time when communication is started, and the security strength is changed in accordance with the distance, and especially when the distance between the devices are short, authentication is not required.